Collagens constitute a large family of extracellar matrix proteins in humans and mammals that provide a structural framework for tissues. A number of hereditary connective tissue diseases are associated with mutations in collagens, including Osteogenesis imperfecta (OI). Collagen-like peptides were synthesized with alterations in primary sequence to represent native and mutation states related to this disease. The peptides were self-assembled in solution and on surfaces to investigate the influence of sequence chemistry on self-organization and, subsequently, how changes in structural organization impact templating for hydroxyapatite (HA) crystallization. Bulkier and more hydrophilic amino acid side chains in the peptide sequence, representing increasing severity of the disease state, resulted in a progressive disruption of the triple helix and supramolecular assembly. These changes also resulted in alterations in the nature of the mineralization pattern and composition of the calcium phosphate deposited on assembled templates.